Anastasia Myskina wasted little time in advancing to the quarter-finals on Thursday, taking just 14 minutes to complete her rain-disrupted encounter with Mary Pierce.

The Russian led 7-6 (7-2) 2-0 when play resumed and swiftly took the second set 6-1 to set up a quarter-final meeting with second seed Justine Henin-Hardenne, scheduled for later on Thursday.

But Myskina refused to criticise US Open organisers, despite her hectic schedule.

"If you are a professional player, you have to prepare for everything," Myskina said.

"If you're here, you have to play. If (the organisers) tell you you have to play two matches (in a day), you have to play.

"So I'm ready to play."

Pierce admitted she had found it difficult to maintain her focus throughout the rain delays.

"I think this was the weirdest situation that I've ever experienced in a Grand Slam tournament," said Pierce.

"It was really, really weird, to wait four days and play 20 minutes to finish the match.

"It's the first time I've gone through an experience like that, and hopefully the last time."

Francesca Schiavone won six straight games to clinch her epic fourth round match with Ai Sugiyama 6-7 (5-7) 7-5 6-2.

The pair began their encounter on Monday but were constantly thwarted by rain in the intervening days.

In a see-saw tussle, Schiavone took the second set when the players resumed on Thursday but the Japanese 16th seed bounced back by taking the first two games of the decider before rain delayed matters once more.

When they returned to the court later, Schiavone wrapped up an incredible victory to seal a quarter-final against Jennifer Capriati, due to be played later on Thursday.